2 * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file net.c Networking-related helper functions. */
11 /* At least NetBSD needs these. */
19 #define AI_ADDRCONFIG 0
29 /** Information about one encrypted connection. */
31 /** Function used to decrypt received data. */
33 /** Function used to encrypt data to be sent. */
36 * Context-dependent data (crypt keys), passed verbatim to the above
41 /** Array holding per fd crypt data. */
42 static struct crypt_data
*crypt_data_array
;
43 /** Current size of the crypt data array. */
44 static unsigned cda_size
= 0;
47 * Activate encryption for one file descriptor.
49 * \param fd The file descriptor.
50 * \param recv_f The function used for decrypting received data.
51 * \param send_f The function used for encrypting before sending.
52 * \param private_data User data supplied by the caller.
54 void enable_crypt(int fd
, crypt_function
*recv_f
, crypt_function
*send_f
,
57 if (fd
+ 1 > cda_size
) {
58 crypt_data_array
= para_realloc(crypt_data_array
,
59 (fd
+ 1) * sizeof(struct crypt_data
));
60 memset(crypt_data_array
+ cda_size
, 0,
61 (fd
+ 1 - cda_size
) * sizeof(struct crypt_data
));
64 crypt_data_array
[fd
].recv
= recv_f
;
65 crypt_data_array
[fd
].send
= send_f
;
66 crypt_data_array
[fd
].private_data
= private_data
;
67 PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd
);
71 * Deactivate encryption for a given fd.
73 * \param fd The file descriptor.
75 * This must be called if and only if \p fd was activated via enable_crypt().
77 void disable_crypt(int fd
)
79 if (cda_size
< fd
+ 1)
81 crypt_data_array
[fd
].recv
= NULL
;
82 crypt_data_array
[fd
].send
= NULL
;
83 crypt_data_array
[fd
].private_data
= NULL
;
88 * Determine the socket type for a given layer-4 protocol.
90 * \param l4type The symbolic name of the transport-layer protocol.
92 * \sa ip(7), socket(2)
94 static inline int sock_type(const unsigned l4type
)
97 case IPPROTO_UDP
: return SOCK_DGRAM
;
98 case IPPROTO_TCP
: return SOCK_STREAM
;
99 case IPPROTO_DCCP
: return SOCK_DCCP
;
101 return -1; /* not supported here */
105 * Pretty-print transport-layer name.
107 static const char *layer4_name(const unsigned l4type
)
110 case IPPROTO_UDP
: return "UDP";
111 case IPPROTO_TCP
: return "TCP";
112 case IPPROTO_DCCP
: return "DCCP";
114 return "UNKNOWN PROTOCOL";
118 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
120 * @param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC)
121 * @param l4type The layer-4 type (\p IPPROTO_xxx).
122 * @param passive Whether this is a passive (1) or active (0) socket/
123 * @param host Remote or local hostname or IPv/6 address string.
124 * @param port_number Decimal port number.
126 * This creates a ready-made IPv4/v6 socket structure after looking up the necessary
127 * parameters. The interpretation of \a host depends on the value of \a passive:
128 * - on a passive socket host is interpreted as an interface IPv4/6 address
129 * (can be left NULL);
130 * - on an active socket, \a host is the peer DNS name or IPv4/6 address to connect to;
131 * - \a port_number is in either case the numeric port number (not service string).
132 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active sockets.
133 * The algorithm tries all possible address combinations until it succeeds.
135 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no matching
136 * connection could be set up (with details in the error log).
138 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2)
140 int makesock(unsigned l3type
, unsigned l4type
, int passive
,
141 const char *host
, unsigned short port_number
)
143 struct addrinfo
*local
= NULL
, *src
,
144 *remote
= NULL
, *dst
, hints
;
145 char *port
= make_message("%u", port_number
);
146 int rc
, on
= 1, sockfd
= -1,
147 socktype
= sock_type(l4type
);
150 * Set up address hint structure
152 memset(&hints
, 0, sizeof(hints
));
153 hints
.ai_family
= l3type
;
154 /* getaddrinfo does not really work well with SOCK_DCCP */
155 if (socktype
== SOCK_DGRAM
|| socktype
== SOCK_STREAM
)
156 hints
.ai_socktype
= socktype
;
158 /* only use addresses available on the host */
159 hints
.ai_flags
= AI_ADDRCONFIG
;
160 if (l3type
== AF_INET6
)
161 /* use v4-mapped-v6 if no v6 addresses found */
162 hints
.ai_flags
|= AI_V4MAPPED
| AI_ALL
;
164 if (passive
&& host
== NULL
)
165 hints
.ai_flags
|= AI_PASSIVE
;
168 * Obtain local/remote address information
170 if ((rc
= getaddrinfo(host
, port
, &hints
, passive
? &local
: &remote
))) {
171 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
173 host
? : (passive
? "[loopback]" : "[localhost]"),
174 port
, gai_strerror(rc
));
175 return -E_ADDRESS_LOOKUP
;
179 * Iterate over all src/dst combination, exhausting dst first
181 for (src
= local
, dst
= remote
; src
!= NULL
|| dst
!= NULL
; /* no op */ ) {
182 if (src
&& dst
&& src
->ai_family
== AF_INET
183 && dst
->ai_family
== AF_INET6
) /* v4 -> v6 is not possible */
186 sockfd
= socket(src
? src
->ai_family
: dst
->ai_family
, socktype
, l4type
);
191 * Set those options that need to be set before establishing the connection
193 /* Reuse the address on passive (listening) sockets to avoid failure on restart */
194 if (passive
&& setsockopt(sockfd
, SOL_SOCKET
, SO_REUSEADDR
, &on
, sizeof(on
)) == -1) {
195 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n", strerror(errno
));
196 return -ERRNO_TO_PARA_ERROR(errno
);
200 if (bind(sockfd
, src
->ai_addr
, src
->ai_addrlen
) < 0) {
205 break; /* bind-only completed successfully */
208 if (dst
&& connect(sockfd
, dst
->ai_addr
, dst
->ai_addrlen
) == 0)
209 break; /* connection completed successfully */
212 if (dst
&& (dst
= dst
->ai_next
))
215 if (src
&& (src
= src
->ai_next
))
216 dst
= remote
; /* restart inner loop */
221 freeaddrinfo(remote
);
223 if (src
== NULL
&& dst
== NULL
) {
224 PARA_ERROR_LOG("can not create %s socket %s#%s.\n", layer4_name(l4type
),
225 host
? : (passive
? "[loopback]" : "[localhost]"), port
);
226 return -ERRNO_TO_PARA_ERROR(errno
);
232 * Create a passive / listening socket.
233 * \param l3type The network-layer type (\p AF_xxx)
234 * \param l4type The transport-layer type (\p IPPROTO_xxx).
235 * \param port The decimal port number to listen on.
237 * \return Positive integer (socket descriptor) on success, negative value otherwise.
238 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
240 int para_listen(unsigned l3type
, unsigned l4type
, unsigned short port
)
242 int ret
, fd
= makesock(l3type
, l4type
, 1, NULL
, port
);
245 ret
= listen(fd
, BACKLOG
);
248 return -ERRNO_TO_PARA_ERROR(errno
);
250 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
251 layer4_name(l4type
), port
, fd
);
257 * Print numeric host and port number (beware - uses static char).
258 * \param sa The IPv4/IPv6 socket address to use.
259 * \param len The length of \p sa.
263 char *host_and_port(struct sockaddr
*sa
, socklen_t len
)
265 static char output
[NI_MAXHOST
+ NI_MAXSERV
+ 2];
266 char hbuf
[NI_MAXHOST
],
270 ret
= getnameinfo(sa
, len
, hbuf
, sizeof(hbuf
), sbuf
, sizeof(sbuf
),
271 NI_NUMERICHOST
| NI_NUMERICSERV
);
273 PARA_WARNING_LOG("hostname lookup error (%s).\n", gai_strerror(ret
));
274 sprintf(output
, "(unknown)");
276 sprintf(output
, "%s#%s", hbuf
, sbuf
);
282 * Look up the local or remote side of a connected socket structure.
283 * \param fd The socket descriptor of the connected socket.
284 * \param getname Either \fn getsockname() for local, or \fn getpeername() for remote side.
286 * \return A static character string identifying hostname and port of the chosen side
287 * \sa getsockname(2), getpeername(2)
289 static char *__get_sock_name(int fd
, int (*getname
)(int, struct sockaddr
*, socklen_t
*))
291 struct sockaddr_storage ss
;
292 socklen_t sslen
= sizeof(ss
);
294 if (getname(fd
, (struct sockaddr
*)&ss
, &sslen
) < 0) {
295 static char *dont_know
= "(don't know)";
296 PARA_ERROR_LOG("can not determine address from fd %d: %s\n", fd
, strerror(errno
));
300 return host_and_port((struct sockaddr
*)&ss
, sslen
);
303 char *local_name(int sockfd
)
305 return __get_sock_name(sockfd
, getsockname
);
308 char *remote_name(int sockfd
)
310 return __get_sock_name(sockfd
, getpeername
);
314 * Send out a buffer, resend on short writes.
316 * \param fd The file descriptor.
317 * \param buf The buffer to be sent.
318 * \param len The length of \a buf.
320 * \return Standard. In any case, the number of bytes actually sent is stored
323 static int sendall(int fd
, const char *buf
, size_t *len
)
329 while (*len
< total
) {
330 int ret
= send(fd
, buf
+ *len
, total
- *len
, 0);
332 return -ERRNO_TO_PARA_ERROR(errno
);
339 * Encrypt and send a binary buffer.
341 * \param fd The file descriptor.
342 * \param buf The buffer to be encrypted and sent.
343 * \param len The length of \a buf.
345 * Check if encryption is available. If yes, encrypt the given buffer. Send
346 * out the buffer, encrypted or not, and try to resend the remaing part in case
351 int send_bin_buffer(int fd
, const char *buf
, size_t len
)
354 crypt_function
*cf
= NULL
;
357 PARA_CRIT_LOG("%s", "len == 0\n");
358 if (fd
+ 1 <= cda_size
)
359 cf
= crypt_data_array
[fd
].send
;
361 void *private = crypt_data_array
[fd
].private_data
;
362 /* RC4 may write more than len to the output buffer */
363 unsigned char *outbuf
= para_malloc(ROUND_UP(len
, 8));
364 (*cf
)(len
, (unsigned char *)buf
, outbuf
, private);
365 ret
= sendall(fd
, (char *)outbuf
, &len
);
368 ret
= sendall(fd
, buf
, &len
);
373 * Encrypt and send null terminated buffer.
375 * \param fd The file descriptor.
376 * \param buf The null-terminated buffer to be send.
378 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
382 int send_buffer(int fd
, const char *buf
)
384 return send_bin_buffer(fd
, buf
, strlen(buf
));
389 * Send and encrypt a buffer given by a format string.
391 * \param fd The file descriptor.
392 * \param fmt A format string.
396 __printf_2_3
int send_va_buffer(int fd
, const char *fmt
, ...)
401 PARA_VSPRINTF(fmt
, msg
);
402 ret
= send_buffer(fd
, msg
);
408 * Receive and decrypt.
410 * \param fd The file descriptor.
411 * \param buf The buffer to write the decrypted data to.
412 * \param size The size of \a buf.
414 * Receive at most \a size bytes from file descriptor \a fd. If encryption is
415 * available, decrypt the received buffer.
417 * \return The number of bytes received on success, negative on errors.
421 __must_check
int recv_bin_buffer(int fd
, char *buf
, size_t size
)
424 crypt_function
*cf
= NULL
;
426 if (fd
+ 1 <= cda_size
)
427 cf
= crypt_data_array
[fd
].recv
;
429 unsigned char *tmp
= para_malloc(size
);
430 void *private = crypt_data_array
[fd
].private_data
;
431 n
= recv(fd
, tmp
, size
, 0);
434 unsigned char *b
= (unsigned char *)buf
;
435 (*cf
)(numbytes
, tmp
, b
, private);
439 n
= recv(fd
, buf
, size
, 0);
441 return -ERRNO_TO_PARA_ERROR(errno
);
446 * Receive, decrypt and write terminating NULL byte.
448 * \param fd The file descriptor.
449 * \param buf The buffer to write the decrypted data to.
450 * \param size The size of \a buf.
452 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
453 * write a NULL byte at the end of the received data.
455 * \return The return value of the underlying call to \a recv_bin_buffer().
457 * \sa recv_bin_buffer()
459 int recv_buffer(int fd
, char *buf
, size_t size
)
464 n
= recv_bin_buffer(fd
, buf
, size
- 1);
473 * Wrapper around the accept system call.
475 * \param fd The listening socket.
476 * \param addr Structure which is filled in with the address of the peer socket.
477 * \param size Should contain the size of the structure pointed to by \a addr.
479 * Accept incoming connections on \a addr. Retry if interrupted.
481 * \return The new file descriptor on success, negative on errors.
485 int para_accept(int fd
, void *addr
, socklen_t size
)
490 new_fd
= accept(fd
, (struct sockaddr
*) addr
, &size
);
491 while (new_fd
< 0 && errno
== EINTR
);
492 return new_fd
< 0? -ERRNO_TO_PARA_ERROR(errno
) : new_fd
;
496 * prepare a structure for \p AF_UNIX socket addresses
498 * \param u pointer to the struct to be prepared
499 * \param name the socket pathname
501 * This just copies \a name to the sun_path component of \a u.
503 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
504 * than \p UNIX_PATH_MAX.
506 static int init_unix_addr(struct sockaddr_un
*u
, const char *name
)
508 if (strlen(name
) >= UNIX_PATH_MAX
)
509 return -E_NAME_TOO_LONG
;
510 memset(u
->sun_path
, 0, UNIX_PATH_MAX
);
511 u
->sun_family
= PF_UNIX
;
512 strcpy(u
->sun_path
, name
);
517 * Prepare, create, and bind a socket for local communication.
519 * \param name The socket pathname.
520 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
521 * \param mode The desired mode of the socket.
523 * This function creates a local socket for sequenced, reliable,
524 * two-way, connection-based byte streams.
526 * \return The file descriptor, on success, negative on errors.
532 int create_local_socket(const char *name
, struct sockaddr_un
*unix_addr
,
537 ret
= init_unix_addr(unix_addr
, name
);
540 ret
= socket(PF_UNIX
, SOCK_STREAM
, 0);
542 return -ERRNO_TO_PARA_ERROR(errno
);
544 ret
= bind(fd
, (struct sockaddr
*) unix_addr
, UNIX_PATH_MAX
);
546 ret
= -ERRNO_TO_PARA_ERROR(errno
);
550 if (chmod(name
, mode
) < 0)
559 * Prepare, create, and connect to a Unix domain socket for local communication.
561 * \param name The socket pathname.
563 * This function creates a local socket for sequenced, reliable, two-way,
564 * connection-based byte streams.
566 * \return The file descriptor, on success, negative on errors.
568 * \sa create_local_socket(), unix(7), connect(2)
570 int create_remote_socket(const char *name
)
572 struct sockaddr_un unix_addr
;
575 ret
= init_unix_addr(&unix_addr
, name
);
578 fd
= socket(PF_UNIX
, SOCK_STREAM
, 0);
580 return -ERRNO_TO_PARA_ERROR(errno
);
581 if (connect(fd
, (struct sockaddr
*)&unix_addr
, sizeof(unix_addr
)) == -1) {
582 ret
= -ERRNO_TO_PARA_ERROR(errno
);
592 ssize_t
send_cred_buffer(int sock
, char *buf
)
594 return send_buffer(sock
, buf
);
596 int recv_cred_buffer(int fd
, char *buf
, size_t size
)
598 return recv_buffer(fd
, buf
, size
) > 0? 1 : -E_RECVMSG
;
600 #else /* HAVE_UCRED */
602 * send NULL terminated buffer and Unix credentials of the current process
604 * \param sock the socket file descriptor
605 * \param buf the buffer to be sent
607 * \return On success, this call returns the number of characters sent. On
608 * error, \p -E_SENDMSG is returned.
610 * \sa okir's Black Hats Manual
613 ssize_t
send_cred_buffer(int sock
, char *buf
)
615 char control
[sizeof(struct cmsghdr
) + 10];
617 struct cmsghdr
*cmsg
;
618 static struct iovec iov
;
624 iov
.iov_len
= strlen(buf
);
628 /* compose the message */
629 memset(&msg
, 0, sizeof(msg
));
632 msg
.msg_control
= control
;
633 msg
.msg_controllen
= sizeof(control
);
634 /* attach the ucred struct */
635 cmsg
= CMSG_FIRSTHDR(&msg
);
636 cmsg
->cmsg_level
= SOL_SOCKET
;
637 cmsg
->cmsg_type
= SCM_CREDENTIALS
;
638 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct ucred
));
639 *(struct ucred
*)CMSG_DATA(cmsg
) = c
;
640 msg
.msg_controllen
= cmsg
->cmsg_len
;
641 ret
= sendmsg(sock
, &msg
, 0);
647 static void dispose_fds(int *fds
, unsigned num
)
651 for (i
= 0; i
< num
; i
++)
656 * receive a buffer and the Unix credentials of the sending process
658 * \param fd the socket file descriptor
659 * \param buf the buffer to store the message
660 * \param size the size of \a buffer
662 * \return negative on errors, the user id on success.
664 * \sa okir's Black Hats Manual
667 int recv_cred_buffer(int fd
, char *buf
, size_t size
)
671 struct cmsghdr
*cmsg
;
677 setsockopt(fd
, SOL_SOCKET
, SO_PASSCRED
, &yes
, sizeof(int));
678 memset(&msg
, 0, sizeof(msg
));
679 memset(buf
, 0, size
);
684 msg
.msg_control
= control
;
685 msg
.msg_controllen
= sizeof(control
);
686 if (recvmsg(fd
, &msg
, 0) < 0)
688 result
= -E_SCM_CREDENTIALS
;
689 cmsg
= CMSG_FIRSTHDR(&msg
);
691 if (cmsg
->cmsg_level
== SOL_SOCKET
&& cmsg
->cmsg_type
692 == SCM_CREDENTIALS
) {
693 memcpy(&cred
, CMSG_DATA(cmsg
), sizeof(struct ucred
));
696 if (cmsg
->cmsg_level
== SOL_SOCKET
697 && cmsg
->cmsg_type
== SCM_RIGHTS
) {
698 dispose_fds((int *) CMSG_DATA(cmsg
),
699 (cmsg
->cmsg_len
- CMSG_LEN(0))
702 cmsg
= CMSG_NXTHDR(&msg
, cmsg
);
706 #endif /* HAVE_UCRED */
709 * receive a buffer and check for a pattern
711 * \param fd the file descriptor to receive from
712 * \param pattern the expected pattern
713 * \param bufsize the size of the internal buffer
715 * \return Positive if \a pattern was received, negative otherwise.
717 * This function creates a buffer of size \a bufsize and tries
718 * to receive at most \a bufsize bytes from file descriptor \a fd.
719 * If at least \p strlen(\a pattern) bytes were received, the beginning of
720 * the received buffer is compared with \a pattern, ignoring case.
725 int recv_pattern(int fd
, const char *pattern
, size_t bufsize
)
727 size_t len
= strlen(pattern
);
728 char *buf
= para_malloc(bufsize
+ 1);
729 int ret
= -E_RECV_PATTERN
, n
= recv_buffer(fd
, buf
, bufsize
);
733 if (strncasecmp(buf
, pattern
, len
))
738 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n
, pattern
);
740 PARA_NOTICE_LOG("recvd: %s\n", buf
);